Speed increasing additives for non-silver light sensitive systems

ABSTRACT

Non-silver photographic compositions of the type described in U.S. Pat. No. 3,481,739 issued Dec. 2, 1969, are increased in photographic speed by the addition of one or more compounds from the group consisting of merocyanine dyes, polyphenylmethane carbinol bases and N-methyl diphenyl amines.

United States Patent Wainer et al.

[ 51 May 2, 1972 [73] Assignee: Horizons Incorporated [22] Filed: July19, 1968 [21] Appl. No.: 746,008

[52] U.S. Cl ..96/90 Field of Search ..96/90 [56] References CitedUNITED STATES PATENTS 3/1970 Yamada et a] ..96/90 Primary Examiner-Norman G. Torchin Assistant Examiner-John Winkelman Attorney-LawrenceI. Field 571 ABSTRACT Non-silver photographic compositions of the typedescribed in U.S. Pat. No. 3,481,739 issued Dec. 2, 1969, are increasedin photographic speed by the addition of one or more compounds from thegroup consisting of merocyanine dyes, polyphenylmethane carbinol basesand N-methyl diphenyl amines.

9 Claims, No Drawings forming compound, such as a leuco di-ortri-aryl-rnethait'e or leuco dye base; at least one activator foraccelerating a color change in said compound, for example CBq; and atleast one N compound.

An exemplary composition according to that patent application contained100 mg of Leuco Crystal Violet, 1.4 grams of CBq, and 15 mg. of'4-picoline-N-oxide, dispersed in a film of polystyrene. The L.E.S. ofthis composition approximated '5 X 10 L.E.S. stands for Light ExposureSpeed and is defined as the reciprocal of the exposure, expressed inmeter candle second, which is required to produce a density (diffusetransmission density) of 0.2 density units above the density o'f'base Iplus fog (see Photographic Science and Engineering, Vol; 8 1964, page98, last paragraph).

Briefly, it has been found that the addition of one or more sensitivitydyes and/or polyphenylmethane ca'rbiriol bases and/or tertiary amines tothe non-silver photosensitive cornpositions of the types described inUS. Pat. No. 3,481,739 enhances the sensitivity of the composition andimproves the photographic speed thereof. These additives may be usedeither singly or in combination with one another to produce the enhancedphotographic speeds characteristic of the present invention. Inaddition, N-vinyl carbazole may be added to increase the contrast(gamma) and maximum derisity.

It has been found that the speed of compositions of the type describedin the above noted patent application, the disclosure of which isintended to be incorporated by reference herein, could be significantlyincreased by the addition of various kinds of materials in suitableamounts, as will appear from the following formulations each of which isexemplary of the addition of various classes of photocatalysts' and/orphotosensitizers to compositions of the type described in saidapplication.

The compositions hereinafter described are prepared in'the same manneras those described in the above-noted patent application and inPhotographic Science and Engineering, Vol. 5, number 2, Man-April 1961,pp. 98 et seq. I

The compositions are each prepared by bringing'the constituents togetherin a suitable solvent-binder solution under a safelight or in totaldarkness, each of the constituents usually being added to the solutionin the order set forth in the examples, then mixed to effect solutionbefore addition of the'next named constituent. After thorough mixing,the composition is applied to a suitable substrate which may bebarytapaper or a film of polyester, glass or other support.

After the composition has been laid down as athin film, itis permittedto dry in air in the dark or under a safelight, drying here meaning theelimination of the solvent(s) from the composition by evaporation. Thenthe composition is photographically exposed for a time sufficient toproduce at least a latent image in the composition.

After this photographic exposure, the latent image in the film isdeveloped by exposing the entire film to radiant energy of anappropriate intensity (e.g.) 50 watt tungsten light source) and suitablewavelength (e.g. between about 600 and 900g). The films are then fixedby means of a solvent rinse consisting of 4 parts of petroleum ether and1 part of acetone.

A composition of the type described in the above noted US. Patent is asfollows:

100 mg. Leuco Crystal Violet mg. 4-picoline-N-oxide 1 g. Carbontetrabromide 4 cc. Polystyrene (10% solution in benzene) Thiscomposition was coated 0.0015 inch on unsubbed 300- D Mylar. Afte'rphotographic exposure,the composition was developed with light filteredthrough a Coming glass filter No. 2412. The formulation produced D,,,,,,of 0.62 and base plus fog of 0.20 and a photographic speed of 1.9 X 10'L.E.S.

EXAMPLE 1 The addition of 6 mg. of Rhodamine B base of the aboveformulation produced a speed of 0.013 L.E.S., 1), of 1.32 and base plusfog 0.36. This illustrates the benefits of adding a dye to such acomposition.

EXAMPLE 2 A photographic speed of 0.04 L.E.S. with acceptable base plusfog levels was achieved by the addition of minor amounts of merocyaninedyes with or without xanthene'type dyes '(R- ho'damine B,etc.). Inaddition, it was found that carbinol compounds of the leucotriphenylr'nethane derivatives appear to be beneficialand increase thedensity 'of the image formed. The following composition producedphotographic speedsof 0.04 L.E.S.:

12mg. Leuco Crystal Violet 5 mg. 4-picoline-N-oxide 5 mg.5-[3-ethyl-2(3H) benzoxazolylidene-ethylidene]- 3-phenyl-2phenylimino-4-thiazolidinone, a merocyanine dye 10 mg. Carbinol opal blue 1.4 g.Carbon tetrabromide 4 cc. 10% Polystyrene in benzene This compositionwas coated 0.0015 inch on unsubbed 300- D Mylar. After photographicexposure, the image was developed with light filtered through a Corningglass filter No. 2030. This composition produced maximum densities ashigh as 1.7 with a base plus fog of0.20.

EXAMPLE 3 A photographic speed-of 0.1 L.E.S. with acceptable base plusfog levels was achieved by the addition of 5 mg of Crystal Violetcarbinol to the formulation represented in Example 2. One compositionproducing photographic speeds of 0.1 L.E.S. was asfollows:

12 mg. Leuco Crystal Violet (stabilized) 5 mg. 4-picoline- N-oxide 5 mg.5-[3-ethyl-2(3H)- benzoxazolylidene-ethylidene ]3-phenyl-2phenylimino-4-thiazolidinone, a'merocyanine dye 5 mg. Carbinol Crystal Violet(stabilized) v, 1 mg. Carbinol Opal Blue (stabilized) 1.4 g. Carbontetrabromide 4 cc. 10% Polystyrene in benzene v The composition'wascoated 0.0015 inch on unsubbed 300- D Mylar. The development lightsource was filtered through a 2030 Corning glass filter. Thiscomposition produced a maximum density of 1.06 with a base plus'fog of0.35.

EXAMPLE 4 Theaddition of a small quantity of a tertiary amine, such asEXAMPLE 5 EXAMPLE 6 The addition of 5 mg. of N-vinylcarbazole to theformulation of Example 5 increased the maximum density to 2.0 andincreased the gamma (slope of H & D plot) of the film.

EXAMPLE 7 A substantial improvement was obtained by the increasedamounts of both the leuco anthracene and carbinol of crystal violet andomitting the leuco crystal violet, as shown in the following formula:

2,7-bis(dimethylamino)-10-pdimethylamino phenyl-9, l dihydro-9,9-dimethylanthracene Carbinol Crystal Violet Carbinol ()pal Blue4-picoline-N-oxide -[3-ethyl2(3H)- benzoxazolylidene-ethylidene]-3-phenyl-2-phenylimino4 thiazolidinone Amine solution 1 drop N-methyldiphenylamine in 5 cc. acetone) Carbon tetrabromide c. percentpolystyrene in benzene 10 mg. 1 mg. 7 mg. 5 mg.

This composition ,produced photographic speeds of 1.0 L.E.S., base fog0.14, with D,,,,, rendition of 1.46.

EXAMPLE 8 Still a further improvement in speed is attained with thefollowing which exhibits an L.E.S. of 2.0 to 4.0, a maximum density of1.4 and a base plus fog ofO.2:

mg. 2,7-bis(dimethylamino)-10-pdimethylaminophenyl-9, l 0- dihydro-9,9-

dimethylanthracene 5 mg. 5-[3-ethyl-2(3H)-benzoxazolylidene-ethylidene]- 3-phenyl-2phenylimino4- thiazolidinone 2mg. 4-picoline-N-oxide l0 mg. Carbinol of crystal violet (stabilized*)1.3 mg. Carbinol of opal blue (stabilized') 6 dropsN-methyldiphenylamine solution 1.4 g. Carbon tetrabromide 4.5 cc. 10%polystyrene in benzene Stabilized by digestion with alkali I dropN-methyldiphenylamine in 5 cc. acetone The stabilization of thecarbinols and leucos in the above formulations is accomplished bydigestion of the carbinols or leucos with an alkali metal hydroxide, asdescribed in U.S. patent application Ser. No. 711,832 filed Mar. 11,1968,.the disclosure of which is incorporated herein by reference.

It will be readily appreciated that in the above formulations, given byway of example, other materials may be used in place of the specificingredients exemplified in the formulations. For

example, other carbinols may be used in place of the carbinols ofcrystal violet or opal blue, and other organic halogen compounds of thetype described in U.S. Pat. No. 3,095,303 and in the U.S. patents listedtherein, preferably those in which three halogen atoms are attached to aterminal carbon atom, may be used in place of CBr iodoform being 'aparticularly preferred replacement for CBr A clear distinction must bekept in mind between the activator described in U.S. Pat. No. 3,481,739and the sensitizers described in the present application. An activatorassists in the rapid production of color from the color-forming compoundwhereas a sensitizer extends the range of actinic radiation to which thecomposition is sensitive.

Each of the compositions described in the preceding examples is utilizedby exposing the same to a pattern of radiation and then developing avisible image by a blanket exposure to radiation in a narrow bandcorresponding to that region to which the composition has beensensitized by the dye formed during the photographic exposure.

In addition, particular note should be made that in Example 8 the amountof N-oxide hasbeen considerably diminished as compared with the amountsutilized in the earlier indicated U.S. patent, this being due in part tothe use of a combination of sensitizers as described.

The purpose of the addition of the sensitizing dye such as amerocyanine'dye is to increase the absorption of visible light so as toincrease the photographic speed.

The purpose of the addition of the polyphenylmethane carbinols is toincrease the photographic speed by an increase in the quantum yield ofdye, i.e., by an increase in the inherent sensitivity of the system toan absorbed photon of visible light.

The purpose of the addition of the tertiary amine is to reduce formationof dye from the color-former by thermal reactions with atmosphericingredients or with other ingredients of the film coating.

The amounts of the additives should be as follows for the best results:

2 to 10 mg./4cc.

l to IOdrops ofa 1%solulion (by vol) in acetonel4cc Sensitizing dyeCarbinol tertiary amine We claim:

1. In a photosensitive composition comprising:

a. at least one color forming compound selected from the groupconsisting of l. leuco diand tri-phenylmethanes; and 2.9,10-dihydroanthracenes represented by the general III III R R whereineach R" is selected from the group consisting of H, alkyl with up to 4carbon atoms and halogen substituted alkyl with up to 4 carbon atoms andeach R' is selected from the group consisting of H and lower alkyl;

b. at least one activator for accelerating the change in said colorforming compound, produced as a result of exposure to a suitable dose ofradiation, from the original compound to a product having a differentcolor, said activator being at least one compound represented by thegeneral formula AiC-X wherein A represents a monovalent radical selectedfrom the group consisting of halogen, alkyl, substituted alkyl,including halogen substituted alkyl, aryl, substituted aryl, aroyl andaralkyl and each X represents a halogen atom selected from the groupconsisting of chlorine, bromine and iodine and all of the Xs need not bethe same;

c. at least one organic N 0 compound; the improvement which comprisesincluding in said composition one or more additional compounds selectedfrom the group consisting of merocyanine dyes, polyphenylmethanecarbinol bases and N-methyl diphenyl amines whereby the photographicspeed of the initial composition is increased as compared with the speedof said composition absent said additional compounds.

2. The composition of claim 12 wherein the N 0 compound is onerepresented by the general fonnula R-N 0 wherein R represents an organicmoiety such that the resulting compound is an N-oxide selected from thegroup consisting of tertiary amines, nitrones, and di-nitrones.

3. The composition of claim 12 wherein the N 0 compound is onerepresented by the general formula wherein R represents atoms of carbon,oxygen, nitrogen or sulfur necessary to complete a 5 or 6 member ring ora fused ring.

4. The composition of claim 1 wherein the activator is a brominesubstituted alkane.

5. The composition including both a leucoanthracene and a merocyaninedye according to claim 1.

6. The combination of claim 5 wherein the merocyanine dye is5-[3-ethyl-2(3H)- H)benzoxazolylidene)-ethylidene1-3-phenyl-2-phenylimino-4-thiazolidinone.

7. The composition of claim 1 wherein there are between 0.1 and 2 partsby weight of N 0 compound for each part by weight of color formingcompound.

8. The composition of claim 1 which includes, in addition, a filmforming resin binder.

9. The composition of claim 1 wherein R" and R are all CH groups in theanthracene.

2. The composition of claim 12 wherein the N -> 0 compound is one represented by the general formula R-N -> 0 wherein R represents an organic moiety such that the resulting compound is an N-oxide selected from the group consisting of tertiary amines, nitrones, and di-nitrones.
 2. 9,10-dihydroanthracenes represented by the general formula
 3. The composition of claim 12 wherein the N -> 0 compound is one represented by the general formula wherein R1 represents atoms of carbon, oxygen, nitrogen or sulfur necessary to complete a 5 or 6 member ring or a fused ring.
 4. The composition of claim 1 wherein the activator is a bromine substituted alkane.
 5. The composition including both a leucoanthracene and a merocyanine dye according to claim
 1. 6. The combination of claim 5 wherein the merocyanine dye is 5-(3-ethyl-2(3H)- H)-benzoxazolylidene)-ethylidene) -3-phenyl-2-phenylimino-4-thiazolidinone.
 7. The composition of claim 1 wherein there are between 0.1 and 2 parts by weight of N -> O compound for each part by weight of color forming compound.
 8. The composition of claim 1 which includes, in addition, a film forming resin binder.
 9. The composition of claim 1 wherein R'''' and R'''''' are all CH3 groups in the anthracene. 